import Component from '@ember/component'; import {alias} from '@ember/object/computed'; import {observer} from '@ember/object'; import {inject as service} from '@ember/service'; export default Component.extend({ tagName: 'aside', classNames: 'gh-alerts', notifications: service(), messages: alias('notifications.alerts'), messageCountObserver: observer('messages.[]', function () { this.sendAction('notify', this.get('messages').length); }) });